This application relates to a retractable ignition system for a burner, an integrated burner with retractable spark ignition system, and methods for igniting a burner using a retractable ignition system.
Many industrial processes, including in the metals industries, use burners that operate for relatively short periods of time and are frequently shut down and re-ignited. In some instances, re-ignition can be required several times a day. Therefore, it is necessary to have an ignition system that is reliable for thousands of ignition cycles, and also able to operate in harsh environments where burners are often used.
A reliable igniter should initiate spark at an appropriate location, i.e., where fuel and oxidizer mix in flammable proportions. Properly locating an igniter is difficult with existing external igniters.
In addition, once the flame is initiated, the ignition system plays no role until the burner is shut down and ignition is required again for restart. However, most existing systems leave the igniter in the furnace during operation of the burner, so that the igniter is exposed to intense radiation from the flame and the furnace, as well as products of incomplete combustion such as soot, which eventually leads to damage of the igniter. Consequently, ignition becomes less reliable and igniters must be maintained and replaced frequently.